In view of world hunger, it is useful to provide the public with a variety of fungicides for use in food agriculture.
Of the 1-hydroxyindoles known in the art, U.S. Pat. No. 3,296,277 dated Jan. 3, 1967 and entitled "Substituted 3-Cyano-1-hydroxy-2-phenylindoles, assigned to Rexall Drug and Chemical Company, Los Angeles, Calif., discloses the compounds 3-cyano-1-hydroxy-2-(o-nitrophenyl)indole and 3-cyano-1-hydroxy-2-(p-methoxyphenyl)indole. The Rexall patent also discloses the use of compounds bearing nitrophenyl or lower alkoxyphenyls as active central nervous system depressants and adrenolytic agents.
While the general structure of 1-hydroxy-2-indoles is known in the art, the fungicidal use of 1-Hydroxyindoles in general has not been disclosed to date. Indeed, "Structure-Activity Relationships of Some Antifungal Indoles", J. Agric. Food Chem., 23(4), 785(1975) by W. H. Dekker, H. A. Selling and J. C. Overeem reports that substitution on the indole nitrogen cancels out fungicidal activity almost completely.
A disclosure by Japanese workers at Kuraray Co., Ltd. reported in Kokai 80-151, 505, November, 1980 contains a disclosure of a series of indole fungicides which included several active N-substituted indoles. Of the active N-substituted indoles reported, none had oxygen substituents.